Heat transfer device for water recovery system

ABSTRACT

A system and method to recover water from an ambient airstream. Dehumidification of the airstream is also achieved by removal of the water. A device of the system includes a chamber having a group of trays that hold respective amounts of liquid desiccant in each tray. A foam media absorbs the desiccant to increase an exposed surface of the desiccant to the airstream. Fans and valves are used to control airflow through the device. A charge cycle circulates air through the device to remove water vapor from the airstream. A subsequent extraction cycle removes water collected in the liquid desiccant by a condenser communicating with the chamber. A heat source adds heat to the chamber before and/or during the extraction cycle. A controller is used to integrate and manage all system functions and input variables to achieve a high efficiency of operational energy use for water collection.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefits of and priority, under 35U.S.C. §119(e), to U.S. Provisional Application Ser. No. 61/655,316,filed Jun. 4, 2012, entitle “WATER RECOVERY SYSTEM AND METHOD,” hereinincorporated by reference in its entirety for all purposes.

FIELD OF THE INVENTION

The invention relates to a water recovery system and method ofrecovering water from ambient air. More particularly, the inventionrelates to an apparatus/device and method using a desiccant solution toextract water from the air, and then separating the water from thedesiccant. The recovered water may be treated to obtain potable water. Abyproduct of the system and method is a stream of dehumidified air thatmay be used for conditioning an interior airspace within a man-madestructure.

BACKGROUND OF THE INVENTION

Potable water is often difficult to obtain in many locations throughoutthe world. In arid climates, there is simply a shortage of water and ifwater is available, it may difficult to make the water potable waterwithout extensive water treatment resources. Even in wet climates,potable water may be in short supply because of the lack of treatmentequipment. Unfortunate events such as war or general political conflictwithin a country often results in diminished infrastructure that wouldnormally have the capability to provide potable water.

There are a number of known solutions for obtaining potable water byremoving water vapor from the ambient air. One known method includespassing an airstream over a cool surface to condense the water vapor.This technique is well known, for example, in heating, ventilating, andair conditioning units (HVAC). In these types of systems, the condensedwater however is usually considered as waste material, and is disposedof.

The use of solid and liquid desiccants is also known for extractingwater from air. In a closed loop process, ambient air is passed througha chamber containing a desiccant soaked media. As the air passes incontact with the media, moisture from the air stream is removed byabsorption into the desiccant. Heat is then applied to the desiccantmedia to vaporize the captured moisture. The water vapor is transportedaway from the chamber, and then condensed and collected. The desiccantis therefore re-concentrated and can be reused in a next water recoveryeffort.

Water recovery systems include the use of both solid and liquiddesiccants. In liquid desiccant systems, one goal is to increase theexposed surface area of the desiccants to the air stream in order tomaximize water vapor removal. One method of achieving this is to spraythe liquid desiccant in a mist onto the media. However, a misting deviceadds to the complexity and cost of the system. Systems with solid formsof desiccants may provide a more compact construction. However, soliddesiccants have relatively small exposed surface areas thereby limitingthe capability to remove water vapor from a passing air stream.

One example of a reference that discloses the use of a liquid desiccantfor recovering water from an airstream is the U.S. Patent ApplicationPublication No. 2011/0232485. The reference provides a compositedesiccant material formed by a porous polyvinyl alcohol (PVA) foam ornon-woven sheets of fiber soaked in a solution of a hygroscopicdesiccant such as calcium chloride (CaCl). The desiccant is held inpores of the fiber material ranging in size from 50 microns to 1000microns. The fiber material is provided in sheets arranged in a stack ina multi-chamber system. During an absorption phase, atmospheric orambient air flows through the chamber. The water vapor is removedthrough contact with the desiccant, and is held in the fiber material.In a water recovery phase, energy is added to the chamber in the form ofheat in order to release the water from the desiccant by evaporation.Fans circulate air through the chamber, and eventually into a waterrecovery chamber within a condensing area. Water is recovered in thecondensing area, and the dried or water lean airstream leaving thechamber may be used to condition a man-made structure. As also set forthin this reference, a control system can be used to operate fans withinthe water recovery system when conditions of humidity and the remainingcapacity of the desiccant stack are conducive to an efficient chargingoperation to remove water from the ambient air. The control system mayalso initiate a regeneration cycle when the availability of low gradeheat energy and the degree of saturation of the desiccant are conduciveto removing water from the desiccant, that is, when the degree ofmoisture in the chamber is high enough relative to the temperature of anavailable cold source for an efficient condensing operation. U.S. PatentApplication Publication No. 2011/0232485 is herein incorporated byreference in its entirety for all purposes.

Another example of a patent reference that discloses a method and devicefor recovering water from ambient air is the U.S. Pat. No. 6,156,102.Specifically, this reference discloses separating water from air by theuse of a liquid desiccant to withdraw water from air, treatment of theliquid desiccant to produce water, and regenerating the desiccant forsubsequent use. In one preferred embodiment, the method disclosedincludes providing a hygroscopic solution comprising a solute in aninitial concentration; contacting the hygroscopic solution with ambientair containing water to obtain a water rich hygroscopic solution havinga concentration of solute less than the initial concentration and awater lean airstream; separating the water lean airstream from the waterrich hygroscopic solution; releasing the water lean airstream to theatmosphere; and treating the water rich hygroscopic solution to obtainwater and to return the hygroscopic solution to its original state forre-use. U.S. Pat. No. 6,156,102 is herein incorporated by reference inits entirety for all purposes.

As described in the U.S. Pat. No. 6,156,102, the effectiveness of liquiddesiccants can be expressed in terms of both their “drying efficiency”and “drying capacity”. Drying efficiency is the ratio of total waterexposed to the hygroscopic solution as compared to the amount of waterremoved. The drying capacity is the quantity of water that a unit massof desiccant can extract from the air. The drying efficiency and dryingcapacity of a hygroscopic solution is in part dependent upon thepressure of the water vapor in the air and on the concentration of thesolute. In general, a hygroscopic solution having a high concentrationof solute and thus a low partial pressure of water vapor in the solute,more quickly absorbs water from air having a higher partial pressure ofwater vapor. Accordingly, the hygroscopic solution has an initial dryingefficiency that is relatively high. As water continues to be absorbedduring a water recovery process, the partial pressure of the water vaporin the solution increases and the rate of water absorption slows down.Eventually, the hygroscopic solution and the air may reach equilibrium,and no more water will be absorbed by the hygroscopic solution. In adesiccant regenerative process for the hygroscopic solution, thecollected water in the hygroscopic solution must be removed. U.S. Pat.No. 6,156,102 is herein incorporated by reference in its entirety forall purposes.

While the prior art may be adequate for its intended purposes, there isstill a need for a water recovery system and method that takes advantageof a modular construction in order to provide an integral capability tocontrol parameters for efficient recovery of water from an ambientairstream. There is also a need to provide a construction that is easilyadaptable to maximize water recovery for a specific application orsituation. There is also a need to provide a water recovery system andmethod in which pre-established logic can be used to control a waterrecovery device based upon known environmental factors and taking intoconsideration the necessary amount of water to be produced. There is yetfurther a need to provide a device and method that requires a minimumamount of energy for operation, and is conducive to accepting forms ofwaste heat for operation. There is also a need to provide a waterrecovery device and method that is reliable, simple to operate, andrequires minimum intervention for daily operations. There is also a needto provide a water recovery device and method that is easy to transport,deploy and commission. There is also a need to provide a water recoverydevice in which monitoring of the concentration of the liquid desiccantsolution is achieved automatically, in order to timely and efficientlyrecover water once the liquid desiccant solution has reached its watersaturation limit. During the regenerative phase of a desiccant solution,it is preferable that the concentration of the desiccant does not becometoo high, which otherwise could result in crystallization orsolidification of the liquid desiccant resulting in a reduced efficiencyof the device until the desiccant chemical can be placed back into itsoptimal concentration with water.

SUMMARY OF THE INVENTION

The present invention includes a system and method for recovering waterfrom an ambient airstream. Additionally, the invention achievesdehumidification of the airstream by removal of the water. The device ischaracterized by a group or stack of trays that hold an amount of liquiddesiccant in each tray. A foam media absorbs or wicks the desiccant toincrease the exposed surface area between the desiccant and theairstream that is passed through an enclosed chamber that holds thedesiccant trays. A number of fans and dampers or valves are used tocontrol the airflow through the chamber.

Operation of the device includes two cycles. The first cycle is a chargecycle in which ambient air is passed through the chamber, across thedesiccant stack, and back to the environment. The desiccant causes watervapor in the airstream to be taken up and held in a foam media materialthat holds the desiccant. In a preferred embodiment, the desiccant is aliquid solution of CaCl and water that is impregnated into the foammedia. The foam media may include a thin sheet of PVA that is arrangedin an accordion folded manner to increase the surface area of the sheetthat is exposed to the airstream. Once the desiccant media has absorbeda sufficient amount of water from the airstream, an extraction cycle isinitiated to recover water from the desiccant solution. In this cycle,the chamber is isolated from the ambient air, and energy is added to thechamber in order to vaporize the water from the desiccant solution. Inaddition to heat energy, the interior pressure of the chamber may bereduced to lower the evaporation temperature required to vaporize thewater. For example, a fan can be used to remove an amount of air withinthe chamber, and then the chamber can be sealed to maintain the lowerpressure state. One or more fans circulate the air within the chamberacross the desiccant media to increase the rate of evaporation. When theinternal temperature of the chamber exceeds a dew point temperature,relative to the external ambient conditions, a condensing circuit isenabled to condense the water vapor from the internal chamber air. Theextraction cycle may also be referred to as a regeneration cycle inwhich the removal of water from the desiccant solution regenerates thedesiccant placing it in a condition for re-use in which theconcentration of the desiccant is returned to an optimal percentage.

Heat energy may be added to the chamber through a water or glycol-basedheat exchanger. There are several possible sources of heat energy thatcan be used to include solar collectors, photovoltaic cells, waste heatfrom nearby industrial sources, electrical heaters, and gas heaters,among others.

The condensed water is captured, and may be further treated in order tomake potable water. For example, the recovered water may be filtered,exposed to an ultra violet light source, mineralized, chlorinated, ormay be otherwise treated to make the water safe for consumption.

A controller is used to integrate and manage all system functions andinput variables to achieve a high efficiency of operational energy usefor water output. The controller uses sensor inputs to estimate theamount of water in the system, the power used, the power stored, and therelevant external and internal environmental conditions such astemperature, pressure, humidity, sunlight/darkness. During theextraction cycle the controller is used to control heat energy added tothe chamber and to also control the condensing rate to therefore sustaincontinuous operation for recovering water from a previous charge cycle.The controller may take advantage of sensor inputs and software thatincorporates a number of algorithms to maximize efficiency of operation.For example, the algorithms may synthesize these inputs to control heatenergy added to the chamber in a manner that minimizes energy usage fromheat delivery systems and from fans and other internal components.During the charging cycle, similar inputs and algorithms can be used tocontrol power consumption of fans and other internal components and toensure a maximum water uptake.

For both system cycles, the algorithms may define optimal operatingconditions for a known geographical area and a known calendar date whichcomprises historical data regarding average temperature, humidity, andsunlight/darkness conditions. From these algorithms, a baselineoperating sequence can be established, and then modified by actualenvironmental conditions at the time. The controller receives multipleinputs that measure temperature, humidity, and pressure of the deviceduring operation. Consequently, the controller manipulates outputs toefficiently operate the device by controlling outputs such as fans,dampers, and heat energy added to the device. During an extraction orregeneration cycle, the controller monitors the amount of water removedfrom the chamber to ensure that too much water is not removed that couldresult in a high desiccant concentration and crystallization of thedesiccant.

In another aspect of control, the invention may include a system inwhich one or more devices may communicate with remote computing deviceswithin a communications network. These remote computing devices can beused to assist in control of the device(s) and to gather data from thedevices or to send updated commands for device operation. Accordinglyeach controller may further include a wireless transmission andreceiving capability. In this regard, a system of the invention maytherefore also include multiple devices, each of the devices having awireless communication capability.

In another aspect of control, the invention may include “location based”capabilities in which Global Positioning System (GPS), magnetometer orother location based sub-systems are used to identify location andorientation of the installed system. This information can be used tofurther exploit data about geographical and/or weather conditions toenable better system efficiencies. For example, knowledge of orientationand duration of sunlight, directions of prevailing winds, etc may beused to obtain better efficiencies for solar energy extraction andminimized fan power needs, respectively.

In another feature of the invention, the device has a modularconstruction in which the desiccant trays can be arranged in a desiredconfiguration. Further, the modular construction takes advantage ofuniform sized tubing and couplers/flanges that allow for easy assemblyand disassembly of the device. Further, the fans and dampers may also beof uniform construction, therefore allowing interchangeability amongcomponents, for ease of assembly/disassembly.

In yet another feature of the invention, the modular construction allowsfor a number of different options for adding heat energy to the device.Each of the desiccant trays may be configured to connect to a heatingassembly. The heating assembly, in a preferred embodiment, may include aheating coil placed in close proximity to heat distribution fins. Theheating assembly itself may be configured as a stackable tray unit.

In yet another feature of the invention, the airflow through the chamberof the device may be dynamically configured to optimize desired waterextraction. For example, each of the desiccant trays may include airflowopenings on one or more sides of the trays that control the direction ofairflow through the chamber. In one example, the airflow may take atorturous path through the chamber in which there is a single or serialpath through each of the desiccant trays. In another example, theairflow may take a parallel flow pattern through the chamber in whichthere may be multiple paths available for airflow through the chamber.Accordingly, airflow through the chamber may be configured to best matchfan capabilities in moving an optimum flow of air through the device.

In yet another feature of the invention, the dried airstream that isproduced when leaving the device may be used for a number ofapplications, such as providing a humidity controlled airstream tocondition an airspace within a building or other man made structure.Particularly in hot, humid climates, the dried airstream produced cangreatly improve working and living conditions within habitable spaces.

Although calcium chloride is disclosed for use as a preferred chemicalhygroscopic desiccant, it should be understood that there are a numberof other hygroscopic desiccants that could be used. For example, lithiumbromide, magnesium chloride, and lithium chloride are known as effectivehygroscopic desiccants. However, one advantage of calcium chloride isthat it is a non-toxic chemical, and is therefore safe to use.

In one aspect of the invention, it can be considered a system forrecovering water from ambient air. In another aspect of the invention,it can be considered an apparatus for recovering water from ambient airwith options for manual control, automatic control, or combinationsthereof. In another aspect of the invention, it can be considered asystem for dehumidifying ambient air for purposes of providingconditioned air for an interior space of a man made structure.

In another aspect of the invention, it may include varioussub-combinations of the system and device. These sub-combinations mayinclude (1) the desiccant stack, (2) the heat exchanger with thedesiccant stack, (3) the desiccant stack and the condenser, (4) thedesiccant stack, heat exchanger, and condenser, and (5) and thedesiccant stack, heat exchanger, and condenser further in combinationwith a controller. Each of these sub-combinations has utility.

Other aspects of the invention include a construction for a desiccantcartridge, a method of selectively controlling air flow through achamber for a water recovery device, a modular construction for a waterrecovery device utilizing easily assembled components, a method forcontrolling a charging cycle of a water recovery apparatus including theuse of algorithms to optimize operation, a method for controlling anextraction cycle of a water recovery apparatus including the use ofalgorithms to optimize operation, a method of operating a water recoverydevice including the use of algorithms to minimize energy usage, amethod of operating a water recovery device including the use ofalgorithms to provide an even and continuous operation of a waterrecovery device, and a method of controlling operation of a waterrecovery device incorporating a plurality of control inputs includingvarious sensors, weigh scales, and flow meters.

Yet further aspects of the invention include a water recovery deviceutilizing multiple energy sources to power an extraction cycle, a methodof determining optimal formulations for a liquid desiccant solution usedwithin a water recovery device, a construction for a desiccant mediaincluding a formulation for a liquid desiccant solution, a waterrecovery device including configurable desiccant media cartridges, amethod for selective and dynamic control of a liquid desiccant solutionused within a water recovery device, a water recovery device includinginsulating and sealing components that effectively isolate airflowthrough the device and otherwise provide optimal temperature andpressure conditions within a chamber of the device, and a method fordetermining an optimal initial desiccant formulation of a water recoverydevice considering relevant geographical data corresponding to thegeographical location where the device is to be installed.

Taking into consideration the above aspects and features of theinvention, the invention can be further described as a water recoverydevice comprising (i) a desiccant stack including a chamber defining anairflow path therein, the stack including a plurality of desiccanttrays; (ii) a condenser communicating with the desiccant stack; (iii) aheat source operative to add heat energy to the chamber; and (iv)wherein an airstream within the water recovery device is warmed prior toor during an extraction cycle, the extraction cycle operative to removea retained water vapor from within the chamber, the condenser providinga cooling source to condense the water vapor and thereby producing anamount of water condensate.

The invention can yet be further described as a water recovery systemcomprising (a) a water recovery device including: (1) a desiccant stackincluding a chamber defining an airflow path therein, the stackincluding a plurality of desiccant trays; (2) a condenser communicatingwith the desiccant stack; (3) a heat source operative to add heat energyto the desiccant stack; wherein an airstream within the water recoverydevice is warmed prior to or during an extraction cycle, the extractioncycle operative to remove a retained water vapor from within thechamber, the condenser providing a cooling source to condense the watervapor and thereby producing an amount of water condensate; (b) acontroller incorporated in the device for controlling functioning of thedevice to include an extraction cycle, the device further including aplurality of sensors as inputs to the controller, and a plurality ofvalves as outputs of the controller, the valves being located within aheat transport line of the device; and (c) said water recovery devicefurther including a communications node incorporated within acommunications system enabling the water recovery device to communicatewithin the communications system.

Further still, a method is provided for recovering water vapor fromambient air, said method comprising: providing a water recovery deviceincluding (i) a desiccant stack having a chamber defining an airflowpath therein, the stack including a plurality of desiccant trays; (iii)a heating source communicating with the desiccant stack for providingheat to the desiccant stack; (iv) at least one heating line, the heatingline communicating with the heat source; (v) at least one heatingelement, the heating element communicating with the heating line, theheating element operative to provide heat to the desiccant stack; andoperating the device in an extraction cycle to remove the retained watervapor within the chamber; and condensing the water vapor by a coolingsource within the condenser thereby producing an amount of watercondensate.

The preceding is a simplified summary of the disclosure to provide anunderstanding of some aspects of the invention. This summary is neitheran extensive nor exhaustive overview of the disclosure and its variousaspects, embodiments, and/or configurations. It is intended neither toidentify key or critical elements of the disclosure nor to delineate thescope of the disclosure but to present selected concepts of thedisclosure in a simplified form as an introduction to the more detaileddescription presented below. As will be appreciated, other aspects,embodiments, and/or configurations of the disclosure are possibleutilizing, alone or in combination, one or more of the features setforth above or described in detail below. Therefore, other features andadvantages of the present disclosure will become apparent from a reviewof the following detailed description, taken in conjunction with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the device of the invention in onepreferred embodiment;

FIG. 2 is an exploded perspective view of a desiccant tray and desiccantmedia cartridge;

FIG. 3 is another perspective view of the desiccant tray with thedesiccant media cartridge mounted within the tray;

FIG. 4 is a vertical section of the desiccant tray of FIG. 2 showingdetails of the arrangement of the desiccant media cartridge and anamount of desiccant solution within the tray;

FIG. 5 is an exploded perspective view of a heat exchanger assembly;

FIG. 6 is a perspective of the assembled heat exchanger assembly of FIG.5;

FIG. 7 is a vertical section of a desiccant tray mounted over a heatexchanger assembly, illustrating the relationship between heatdistribution elements of the heat exchanger and the desiccant tray;

FIG. 8 is a perspective view of a heat exchanger tray with a heatexchanger mounted in the tray;

FIG. 9 is a fragmentary perspective of the device in a preferredembodiment;

FIG. 10 is a perspective view of a preferred embodiment of a desiccantstack including a plurality of vertically stacked desiccant trays, aheat exchanger assembly located beneath the desiccant trays, and a stackexhaust manifold for directing exhaust air from the desiccant stack;

FIG. 11 is a vertical section of FIG. 10 illustrating the relationshipbetween the desiccant trays and the heat exchanger assembly;

FIG. 12 is a schematic diagram of a desiccant stack, and oneconfiguration for an airflow path through the chamber, referred toherein as a parallel flow path;

FIG. 13 is another schematic diagram of a desiccant stack, and anotherconfiguration for an airflow path through the chamber, referred toherein as a serial flow path;

FIG. 14 is an exploded perspective of components of the device includinga fan and damper/valve combination;

FIG. 15 is an assembled perspective of the components of FIG. 14;

FIG. 16 is a schematic diagram of components of a controller that may beused in conjunction with control of the device; and

FIG. 17 is a schematic diagram of a communication system, including aplurality of devices with integral controllers operating within acommunications network in which one or all of the devices maycommunicate with other communication nodes of the network, to includedownload and upload of data and commands.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, a schematic diagram is shown for purposes ofillustrating the major functional components of a device of the system.Specifically, the device 10 includes a housing 12 that defines thereinan interior space or chamber for receiving a flow of air to remove watervapor from the airstream. The chamber is more specifically defined asincluding a desiccant stack 14 including a plurality of desiccant trays74 (see FIG. 2) that each holds a desiccant media material.

Each of the trays 74 have a quantity of a liquid desiccant solutionplaced in contact with the desiccant media material that wicks orabsorbs the solution, as set forth further below with respect to thedescription of the FIGS. 2-4. The device 10 further includes one or moreheat exchanger assemblies 16 for providing heat to the chamber. A weighscale 18 is used to monitor the mass of water vapor that is collectedfrom the airstream during a charge cycle, as well as the mass of watervapor that is removed from the liquid desiccant solution during anextraction cycle.

An ambient or environmental or ambient air intake line 20 provides anentry point for the ambient air to enter the chamber area. The ambientair entering the chamber follows a flow path 22 through the heatexchanger assembly 16 and the desiccant stack 14. In the schematicdiagram of FIG. 1, the flow path 22 illustrates a winding or torturouspath, which is explained in more detail below with respect toconfigurable flow paths shown in the FIGS. 11 and 12. An exhaust line 24returns the airstream that has traveled through the chamber back to theatmosphere. Alternatively, the exhaust line 24 may communicate withductwork of a man made structure (not shown) to provide a conditionedairstream for the structure.

The airstream through the chamber may take one of several paths,depending upon the particular cycle in which the device is operating atthe time. In the case of a charge cycle, the airstream is exhausted tothe atmosphere or manmade structure through the exhaust line 24. Duringan extraction cycle, air within the chamber exits the chamber throughthe condenser inlet line 26 that interconnects the chamber with thecondenser 28. Also during an extraction cycle, prior to when air withinthe chamber reaches the desired saturated state ready for condensing,air is re-circulated through the chamber by re-circulating line 72, asalso discussed below.

FIG. 1 also schematically illustrates a cooling coil 30 that is used tocondense the moist airstream for extraction of water vapor from theairstream. An ambient air cooling line 32 is also illustrated within thecondenser 28. During the extraction cycle, ambient air is used as thecooling source for condensing the warmer, moist airstream that hasentered the cooling coil 30. A water collection container 34 is providedfor collecting the condensed water by water line 36 that interconnectsthe condenser 28 to the container 34. A weigh scale 38 may also be usedto monitor the amount of water extracted. In conjunction with scale 18,the scale 38 provides control inputs for monitoring water recovery.

The heat exchanger assembly 16 includes a heat source 40. The heatsource 40 in the schematic of FIG. 1 is shown as a solar collector orphotovoltaic cell; however the heat source could be many other sourcessuch as an electric or gas heater, or available waste heat sources. Forexample, the heat source could include waste heat from an industrialprocess, or waste heat captured from the exhaust manifold or engine of avehicle. A closed loop heating line 44 is used to re-circulate an amountof heating fluid. As shown, the heating line 44 traverses through thechamber and in close proximity with the desiccant stack 14. The heatingfluid 42 may be a conventional heating fluid such as water or glycol. Aheating fluid container 45 is provided to store the heating fluid. Afluid pump 70 is used to re-circulate the heating fluid 42 through theheating line 44. Although FIG. 1 illustrates the heat source 40 andcontainer 45 as separated from the other components of the heatexchanger assembly 16 within the chamber, it shall be understood thatthe heat exchanger assembly 16 could be housed in a number of differentconfigurations to accommodate the particular application which thedevice is being used.

A controller 84 may be used to provide automatic control of theoperation of the device. The controller 84 may take the form of knownindustrial controllers that accommodate control inputs and outputs, anda processor with integral software or firmware. With respect to inputs,the device may be monitored by a number of temperature sensing devices46, such as thermocouples or RTDs. In FIG. 1, there are a number oftemperature sensors shown at various locations throughout the device.Within the heat exchanger assembly, a number of temperature sensingdevices 46 are also shown to include sensors located within the heatexchanger, and within the heating line at the entrance and exit from theheat source 40. A number of temperature sensors are also illustratedwithin the desiccant stack 14, as well as within the condenser 28.

In addition to temperature control, the FIG. 1 also illustrates a liquidflow sensor 48 that measures the flow rate of the heating fluid 42through the heating line 44. An airflow sensor 49 may also beincorporated within the exhaust line 24 to monitor the flow rate of airthrough the chamber. Further, a number of relative humidity sensors 50may be incorporated within the device to measure relative humidity ofthe airstream. As shown in FIG. 1, relative humidity sensors 50 may beco-located with temperature sensors 46 at the exhaust line 24, at thecondenser return line 73, and at other selected locations in which itmay be desirable to monitor the relative humidity.

With respect to controlling airflow through the device, a number of fansmay be used to precisely control airflow. Referring again to the FIG. 1,the fans may include an intake fan 52 communicating with the air intakeline 20, an exhaust fan 56 that communicates with the exhaust line 24, acondenser fan 68 that introduces air into the condenser 28 alongcondenser inlet line 26, a re-circulating fan 64 that re-circulates airthrough the chamber through re-circulating line 72, and an ambient aircooling fan 69 that introduces ambient air into the condenser 28.Control of air flow through the device is also achieved through a numberof dampers or valves. Again referring to the FIG. 1 valves used tocontrol air flow may include an air intake valve 54 mounted in the airintake line 20, an exhaust valve 58 that is mounted in the air exhaustline 24, a condenser inlet valve 62 that is mounted in the condenserinlet line 26, and a re-circulating valve 66 that is mounted in thecondenser return line 73.

Referring now to FIGS. 2-4, a desiccant tray 74 is illustrated inaccordance with a preferred embodiment. The tray 74 includes sidewalls90, and a base 96. One or more of the sidewalls 90 may include rodreceiving channels 94 that receive rods or dowels (not shown) thatstabilize the connection between stacked trays 74. At least one pair ofopposing sidewalls 90 may include an interior flange 92 for mounting asealing gasket 75 (see FIG. 8). Preferably, there is a sealing gasketplaced between each stacked tray 74 to thereby limit airflow lossthrough the chamber. The base 96 holds an amount of liquid desiccantsolution 110 (FIG. 4). The base 96 includes base sidewalls 98, and oneor more of the sidewalls 98 may include a plurality of airflowcirculation slots or openings 100. As shown, these openings 100 aredisposed at the upper portion of base sidewalls 98, above the liquidline 112 of the liquid desiccant solution 110, and below the top edge ofthe sidewalls 90. FIGS. 2-4 also illustrate a desiccant media cartridge82 that is placed within the desiccant tray 74, as best illustrated inthe FIG. 3. The media cartridge 82 is shown as a rectangular shapedelement that fits within the confines of base sidewalls 98. The mediacartridge 82 includes a media frame 102 that holds media material 120 inan accordion folded configuration. The media frame 102 may also includeone or more frame panels 104 that can be used to direct airflow throughthe chamber by preventing air from passing through the panels 104. Inthe FIG. 2, it is intended to show that the two end walls of the mediaframe 102 include media frame panels 104, while the opposing sidewallsof the media frame 102 remains open thereby allowing airflowhorizontally through the media cartridge 82. In order to stabilize theopen sides of the frame 102, the frame may further include screensupports 106 comprising a plurality of wire elements as shown.

Referring to FIG. 4, the media material 120 is illustrated in the formof a thin sheet that is held in the accordion folded configuration tothereby maximize the exposed surface area of the media material to airpassing through the chamber. As shown, the desiccant solution 110 fillsa portion of the base 96, and the lower end of the media material 120 issubmerged in the fluid solution 110. As mentioned, one example of anacceptable media material may include a thin sheet of PVA foam, anabsorbent foam that readily wicks the desiccant solution 110. In orderto maintain the media material in the accordion folded configurationwith uniform gaps or spaces between the folds of material, an internalwire support 122 may be used for stabilizing the media material. Whenthe media material 120 absorbs or wicks the desiccant solution 110, thematerial serves to evenly distribute the desiccant solution in largesurface area within a confined space. Accordingly, the media material120 and the desiccant solution 110 provide a hygroscopic feature toeffectively remove water vapor from a passing airstream. As shown in theFIG. 4, the media material 120 is preferably oriented in a parallelrelationship with the flow of air, thereby enabling air to pass throughthe gaps between the folds of the media material. In this orientation,the airstream maintains significant contact with the exposed surfaces ofthe media material. As air continues to flow through a media cartridge82, the amount of water vapor retained in the media material increases.It is possible for the amount of retained water vapor to exceed theliquid holding capacity of the media material, resulting in dripping ofthe desiccant solution into the pool of desiccant fluid 110. Asdiscussed further below, it is advantageous to begin an extraction cycleprior to complete saturation of the media material.

The thickness of the media material, as well as the configuration of themedia material in terms of the size of the gaps between folds of themedia material can be adjusted to meet the desired water recovery needsfor a particular use. Thinner sheets of material with larger gapsbetween folds of the material allows for better airflow through thechamber, thereby reducing the airflow pressure drop through the chamber.However, this configuration of the media material limits the amount ofwater vapor that can be removed from the airflow. Reducing the size ofthe gaps between the folds of the media material and increasing thewidth of the media material results in increased capability to removewater from the airflow, but with the disadvantage of increased pressuredrop through the chamber therefore requiring greater fan capacity inmoving air through the chamber. It is therefore contemplated to adjustthe particular configuration of the media material so that waterrecovery is achieved to meet the needs of the particular use of thedevice without excessive air pressure drop through the device that mayexceed the capacity of the fans.

The desiccant solution 110 is placed in each of the trays 74. This maybe done manually at the start of operation of the device. As the devicecontinues to operate, it may be necessary to replenish the desiccantsolution. For example, some portions of the desiccant media that absorbthe desiccant solution may become dried and crystallized, therebypreventing reactivation of the desiccant chemical without cleaning andre-soaking the desiccant media. In lieu of manually replacing thedesiccant solution 110, it is also contemplated that the desiccantsolution 110 may be automatically replenished. A desiccant solutionreservoir (not shown), and a water reservoir (not shown) may have fluidconveying lines that connect to each or selected ones of the trays 74.Each of the trays may also include a liquid level sensor (not shown)and/or a desiccant concentration sensor (not shown) to sense theconcentration of the chemical desiccant. Chemical concentration sensorsare devices that measure the electrical potential of a solution, andchanges in the electrical potential correspond to known changes in theconcentration of a chemical within the solution. Based on inputs fromthese sensors, replenishment valves (not shown) mounted in the fluidconveying lines could be selectively opened to release a designatedamount of water and/or desiccant solution in order to replenish thedesiccant solution in the trays. In many cases, it may only be necessaryto add water back to the desiccant solution in order to place it at theoptimum desiccant concentration.

Referring now to FIGS. 5 and 6, components are illustrated for the heatexchanger assembly 16 that may reside below a desiccant stack 14. Asshown, the assembly includes a housing 76, including sidewalls 130 and abottom wall or base 128. One side of the housing 76 includes a tubingmanifold 132 with openings to receive corresponding tubing sections 134.Extending upward from the base 128 is a plurality of baffles 140 thatare used to support the heating distribution element 78. As shown, theheating distributional element 78 may be an accordion folded elementthat fits between the sidewalls 130 and disposed above the heating line44. The heating line 44 is configured in a winding path to thereby moreevenly transfer heat to the heat distribution element 78. The heatingline 44 passes through one of the sidewalls 130 as shown in FIG. 6, andcommunicates with the heat source 40 and container 45 (FIG. 1).Optionally, a wire support element 136 maybe disposed within the housing76 in order to maintain the heating element 78 in its accordion foldedconfiguration. The heat distribution element 78 may be made fromaluminum or another type of corrosive resistant conductor. The housing76 may also include rod receiving channels 138 that align with channels98 of the desiccant trays 74 to receive stabilizing rods (not shown)that help to hold the desiccant stack and heat exchanger assembly in astabilized vertical orientation.

Referring to FIG. 7, the arrangement of a desiccant tray 74 is shownwith respect to the heat exchanger housing 76. As shown, the base orbottom portion of the desiccant tray 74 is located in close proximity tothe upper surfaces the heat distribution element 78. This orientationmay allow for most efficient heat transfer to the overlying tray 74.FIG. 7 also illustrates the available space for air entering the devicein which the air first passes through the gaps between adjacent sectionsof the heat distribution element 78. The airstream is then directedupwards, through the openings 100 in the base sidewall 98 of the tray.Next, air is forced horizontally through the gaps in the media material120 and substantially parallel with the orientation of the mediamaterial 120. The air then travels upward into the next desiccant tray74. The path of airflow through this next desiccant tray may be dictatedby the orientation of the openings 100 in the base sidewalls 98 of thetray.

Further, it is contemplated that a desiccant stack may take advantage ofmultiple heat exchanging assemblies powered by a single source of power.For example, a desiccant stack 14 may include one or more heat exchangeassemblies such as heat exchange assembly16 or heat exchange assembly816, which are disposed throughout a desiccant stack 14 and between oneor more desiccant trays 74. As shown in FIG. 8, heat exchanger assemblycomponents, such as a heat distribution element 878, a heating line 844,and one or more sensors, may be housed in a modified tray 876. Modifiedtray 876 may be modular in design such that tray 876 may be placedwithin a desiccant stack 14; that is, tray 876 may be stacked on top ofdesiccant trays 74, and/or desiccant trays 74 may be stacked on top oftray 876.

As shown in FIG. 8, heating assembly 816 may include similar componentsto those of heating assembly 16. As shown, heating assembly 816 includesa housing 876, sidewalls 890 and a bottom wall or base 898. The heatingdistributional element 878 may be an accordion folded element that fitsbetween the sidewalls 890 and disposed below the heating line 844. Theheating line 844 is configured in a winding path to thereby more evenlytransfer heat to the heat distribution element 878. The heating line 844eventually passes through one of the sidewalls 870 and communicates withthe heat source 40. Heating line 844 may or may not connect to container45 (FIG. 1), depending on whether heating element 844 is a fluid typeheating line or an electrical type heating line.

Heating line 844 may be configured to communicate with heat source 40 ina variety of ways. For example, heat source 40 may communicate with heatexchange assembly 16 and one or more heat exchange assemblies 816 usinga plurality of fluid distribution lines. The plurality of fluiddistribution lines may be arranged in a parallel or serial manner suchthat each heat exchange assembly 16 and/or heat exchange assembly 816directly communicates with the heat source 40. Alternatively, or incombination, the plurality of fluid distribution lines may be arrangedin a serial manner—that is, each heat exchange assembly 16 or 816 maycommunicate directly with a previous heat exchange assembly 16 or 816,In such a serial configuration, Heating line 44 or 844 may further beconfigured to connect to a fluid distribution line utilizing quickconnect fittings to further modularize the installation and removal ofheating assembly 816 in a desiccant stack 14.

Similar to desiccant tray 74, heat exchange assembly 816 includessidewalls 898, and one or more of the sidewalls 898 may include aplurality of airflow circulation slots or openings 800. As shown, theseopenings 800 are disposed at the upper portion of base sidewalls 898.Openings 800 direct the airflow in an orientation most efficient fortransferring heat from heat exchange assembly 816 to the surroundingairstream. For example, the airstream may first enter the heat exchangeassembly 816 through openings 800. The airstream then is forcedhorizontally through the gaps between adjacent sections of the heatdistribution element 878. The airstream is then directed upwards,through the openings 800 in the base sidewall 898 of the tray. The airthen travels upward into a desiccant tray 74.

It is further contemplated that the heat exchange assembly 16 and/or theheat exchange assemblies 816 are capable of regulating a temperaturewithin each of their respective housings or trays. Heat exchangeassembly 16 or heat exchange assembly 816 may be connected in eitherserial or parallel distribution configuration. For example, heatexchange assembly 16 or 816 may include a series of temperatureregulation valves to control an amount of fluid that flows through heatdistribution line. The amount of fluid that flows through a heatdistribution line may be proportional to the amount of heat required towarm an airstream within the chamber at specific point in time. Forinstance, when initiating an extraction cycle, a large delta may existbetween a current temperature of an airstream and a desired temperatureof an airstream; therefore, a large amount of heat may initially berequired to bring the temperature of the airstream, within the chamber,to an optimal or efficient level. By increasing the flow of fluidthrough heat exchange assembly 16 and/or heat exchange assembly 816, theheat distribution lines flowing through heat exchange assembly 16 andheat exchange assembly 816 would be able to distribute this largerquantity of heat. Once a desired temperature within the chamber has beenreached, the flow through heating line 44 or 844 may then be reduced tomaintain the temperature within the chamber and/or the temperature ofthe airstream. If housing or trays are connected in a serialdistribution manner, a bypass valve located near an entrance of eachheat exchange assembly 16 or heat exchange assembly 816 may be required.

The flow rate of the fluid, along with the temperature of fluid, impactthe temperature of the airstream when pump 70 is recirculation theheating fluid throughout heat exchange assemblies 16 and 816. Similar tothe liquid flow sensor 48 as described above, there may be one or moreliquid flow sensors that measure the flow rate of the heating fluid 42through the various heat exchange assemblies 16 or 816. The one or moreliquid flow sensors may provide a flow rate to the controller 200; thatis, the controller 200 is configured to monitor the flow rate of a fluid42. Based in part on the airstream temperature as measured at variouslocations throughout the desiccant stack 74 and tubing assemblies, fluidpump 70 may be instructed to increase or decrease its output bycontroller 200 accordingly. Additionally, configurable valves, includingfluid bypass valves, may be adjusted to alter a flow rate at a specificlocation within the device, such as a particular heat exchange assembly.Further, as the heating fluid is circulated, it may be necessary to warmthe heating fluid to a desired temperature. Controller 200 may directthe heating source 40 to warm the fluid to a specified temperature inaccordance with desired operating conditions.

In another embodiment, in addition to or in lieu of using heat exchangeassembly 16 or 816, other configurations or devices may be used to addheat to the device or system. For instance, the airstream may be passedthrough an inline radiator 99 residing in re-circulating line 72. Aninline radiator may further connect to container 45; with a fluid pumpsimilar to or the same as fluid pump 70 providing a recirculation sourceof heated fluid 42.

In another embodiment, multiple energy sources and varying methods ofdelivering heat may be utilized to add heat to the device 10. Forexample, under some operating conditions and in some environments, itmay be more efficient to utilize an electric heating element to provideadditional heat necessary to increase the temperature of the passingairstream. Such an electrical heating element may be disposed in theheat exchange assembly 16 and may be used instead of heating line 44.Similarly, an electrical heating element may be disposed in heatexchange assembly 816 and used instead of heating line 844. When anelectrical heating element is utilized in varying configurations, afluid distribution system, such as fluid container 45, fluid heater, andfluid distribution piping may not be necessary. Instead, electricalconnections are configured to link a power source 40 to the electricalheating element.

In another embodiment, heating elements may be disposed in variousplaces throughout the device 10. For example, heating element 105 (FIG.2) may be disposed at both ends of a desiccant media frame 102 and mayact more like a forced convection heater. That is, if heating element105 is an electrical heating element, electricity may pass through theelement, warming the surrounding air. Air passing through a desiccantmedia frame 102 may be warmed. A desiccant media frame 102 may beconfigured with the necessary electrical connections to operativelyconnect heating element 105 with a power source, such as power source40. Of course, appropriate environmental electrical connections arerequired when an electric heating element is disposed in close proximityto a desiccant media or if an electric heating element is disposed in ahumid or wet environment.

In another embodiment, an electrical heating element(s) may be placedacross opening 100, as shown in FIG. 3. As shown, heating elements 103warm the airstream passing through openings 100. Similar to theelectrical heating elements 105, when air passes over heating elements103, the passing air, in conjunction with the heating elements, act morelike a forced convection heater. That is, electricity passes through theelement and warms the surrounding air flowing through openings 100. Inthis embodiment and others requiring an electrical connection, anelectrical connection is made amongst a stack of desiccant trays suchthat the necessary electrical energy is provided. For instance,electrical connectors capable of withstanding the environmentalconditions located on the top and bottom of a desiccant tray may providethe necessary electrical connections. Alternatively, or in addition, theelectrical connections may reside at other locations through the device.Similarly, electrical heating elements 103 may be placed across openings800.

In another embodiment, the heat exchange assemblies 16 and 816 are usedto provide a consistent airstream temperature within the stack ofdesiccant media trays, as previously described. However, upon initiatinga water extraction cycle, electrical heating elements, such as heatingelements 103, 105, and 844 may be used to augment or add additional heatto the system as necessary.

Referring to FIG. 9, a preferred embodiment is illustrated for thedevice10. More specifically, a preferred embodiment is illustrated withrespect to construction details for the desiccant stack 14, heatexchanger 16, and the group air conveying elements including fans,valves, conveying lines, and connectors. More specifically, FIG. 9illustrates a desiccant stack 14 arranged in a plurality of desiccanttrays 74 stacked vertically upon one another over a single heatexchanger assembly 16. The most upper tray 74 is removed forillustration purposes to shown a sealing gasket 75 that is placedbetween stacked trays. The stack exhaust manifold 80 is also shown inwhich airflow from the chamber is returned to the atmosphere throughlines 24. As shown in this embodiment, instead of a single exhaust line24, there is a pair of exhaust lines 24 arranged as the outside pair ofconveying lines in the group of four adjacent lines. The embodiment ofFIG. 9 is intended to illustrate that some of the conveying elements maybe provided in duplicate for better airflow control of the device.Accordingly, in addition to duplication of the exhaust lines 24 andassociated fans and valves, the FIG. 9 also illustrates duplication ofthe condenser inlet line 26, re-circulating line 72, return line 73, andthe associated valves and fans for these lines. Because of the angle ofview in FIG. 9, another inlet line 20 and associated conveying elementscannot be seen, but the FIG. 8 is intended also to represent that therecan also be duplication of these elements. In FIG. 9, the condenser 28is shown in a schematic form only, and it shall be understood that thedistal free ends of the lines 26 interconnect with the inlet of the coil30. Additionally, the FIG. 9 does not illustrate the other components ofthe condenser as shown in the FIG. 1, but it shall also be understoodthat the condenser includes these other elements.

In terms of the modular construction of the device, it is clear that thedesiccant trays 74 may be conveniently stacked on top of one another ina space saving arrangement. Additionally, the location of the variousfans and valves may be conveniently located adjacent the desiccant stackto maintain a relatively small device profile. The lines for conveyingairflow may be a plurality of uniform tubing sections, and the tubingsections may connect to one another by a friction fit. Therefore, it isunnecessary to provide sealing gaskets between each and every tubingsection. As discussed in more detail below with respect to the FIGS. 14and 15, the modular construction of the invention further allows forfriction fit attachments between the sections of tubing and the variousvalves and fans.

Referring to FIG. 10, a desiccant stack 14 is illustrated in the samearrangement as shown in the FIG. 9, but with the various tubingsections, valves, and fans removed. Referring to the FIG. 11, thisvertical cross-sectional clearly illustrates the compact and orderlyarrangement of the desiccant trays when placed in a verticalconfiguration. Although the FIGS. 10 and 11 illustrate a verticaldesiccant stack arrangement; it is also contemplated that a desiccantstack could include combinations of both vertically and horizontallyextending desiccant trays. Accordingly, with respect to a horizontallyextending group of desiccant trays, each of the desiccant trays couldalso include a tubing manifold 132 in lieu of solid sidewalls 90 and 98enabling horizontally adjacent trays 74 to communicate with one anotherby tubing sections interconnecting the trays by their correspondingmanifolds 132. Therefore, one can appreciate the highly configurablenature of the device in terms of adjusting its shape and size for aparticular use. For uses of the device with greater water recoveryrequirements, a larger number of trays can be used to increase waterrecovery, or uses of the device with lesser water recovery requirementsmay dictate a fewer number of trays be used. The requisite number of airconveying lines, fans, and valves can be added to a desiccant stack toensure proper airflow through the device for purposes of bothmaintaining airflow through the device during a charging cycle, as wellas airflow through the device during an extraction cycle.

Referring to FIGS. 12 and 13, in yet another aspect of the invention, itis contemplated that a user may dynamically configure the flow path ofair through the device in order to maximize efficiency for the intendeduse of the device. In the example of FIG. 12, a parallel flow path isillustrated by the directional arrows in which each of the trays 74 haveopposing base sidewalls 98 with openings 100, which therefore allowsairflow to travel upwards in a vertical manner through the chamber andalso horizontally through the media cartridges 82. The only blockedsidewall with no openings 100 is the solid sidewall 180 located abovethe heat exchanger assembly 16. This sidewall 180 ensures the airinitially passes through the heat exchanger for purposes of heating theair, for example, during an extraction cycle. As shown in the FIG. 11air may travel horizontally through either a first lower mediacartridge, or the media cartridge in the second or next higher tray 74.

In the example of FIG. 12, the directional arrows show a torturous orserial flow path that is provided through the chamber of the device.Accordingly, alternating and opposite sidewalls of the stacked desiccanttrays 74 include the solid sidewalls 180 without openings 100. One canappreciate the advantages of the dynamic and modular construction of thepresent invention in which the trays can be placed not only in variouscombinations of vertical and horizontal arrangements, but also each traymay be configured with either solid sidewalls 180 or sidewalls 98 withopenings 100 in order to establish a desired airflow path through thechamber, and thereby maximizing airflow for the intended use of thedevice.

Referring now to FIGS. 14 and 15, an example construction is providedfor a valve or damper and fan combination. As shown, in the schematicdiagram of FIG. 1, airflow control through the device includes variouspairs of fans and dampers. Accordingly, the FIGS. 14 and 15 are intendedto illustrate how these various pairs of fans and dampers may beconstructed in accordance with the advantages of the modularconstruction of the invention. A fan assembly 150 is shown as includinga fan housing 158 disposed between a pair of fan flanges 156. The fan160 is disposed within the fan housing 158, and includes acharacteristic fan hub, and a plurality of fan blades. A valve assembly152 connects to the fan assembly. A single connecting flange 162 may beplaced between the valve assembly and fan assembly. The construction ofthe valve assembly 152 may include two half sections, shown as upperhalf section 164 and lower half section 166. The flapper or valveelement 168 has a mounting pin 170, which is received in the pinopenings 174 of the upper half section 164. Pin locks 172 may be used tosecure the ends of the mounting pin 170. As also shown in FIG. 13, anadjacent tubing or conduit section 154 may be secured to the fan also bya single connecting flange 162. Similarly, the opposite end of the valveassembly 152 may connect to an adjacent tubing section 154 by a singleconnecting flange 162. The tubing sections 154 may simply befrictionally received within the adjacent flanges 162. The half sections164 and 166 may be secured to the flanges 164 also by a friction fit, asachieved by the flange extensions 176, or by some other connecting meansin which substantial airflow loss is limited between the connections. Asalso shown, the fan 150 may be secured to its abutting flanges 162 as bya screw and nut combination. The FIGS. 14 and 15 are intended toillustrate an example construction in which pairs of fans and valves maybe connected to one another in line with sections of tubing, wherein theconstruction is simple, reliable, and repeatable without the need forspecial tools or equipment. Thus, functionally distinct pairs of fansand valves of the device when installed in the device may be assembledby similar assembly methods.

Additionally, flapper or valve element 168 may be dynamically controlledvia an integrated controller 84.

In order to control the device, an integral controller 84 (FIG. 1) maybe used. While manual control is also possible, use of a controller hasa number of advantages to include less burdensome user efforts, and moretimely and precise control of the device for producing the desiredamount of water. The controller 84 may be a known industrial controller,such as a programmable logic controller (PLC).

Referring to the FIG. 16, this figure is intended to represent thecontroller 84 as a computing device 200 with known functionality. Morespecifically, FIG. 16 illustrates one embodiment of a computing device200 comprising hardware elements that may be electrically coupled via abus 255. The hardware elements may include one or more centralprocessing units (CPUs) 205; one or more input devices 210 (e.g., amouse, a keyboard, etc.); and one or more output devices 215 (e.g., adisplay device, a printer, etc.). The computing device 200 may alsoinclude one or more storage device 220. By way of example, storagedevice(s) 220 may be disk drives, optical storage devices, solid-statestorage device such as a random access memory (“RAM”) and/or a read-onlymemory (“ROM”), which can be programmable, flash-updateable and/or thelike. The controller 200 also includes one or more input/output modules201. The input/output modules may be built in with the controller, ormay be one or more external input/output modules that plug into thecontroller. For PLCs, most of these are equipped with extensiveinput/output module capabilities in which a wide range of inputs andoutputs may be accommodated. Further, because PLCs are typically madefor severe operating conditions, the use of a PLC as a controller in thedevice of the invention may be a preferred option.

The computing device 200 may additionally include a computer-readablestorage media reader 225; a communications system 230 (e.g., a modem, anetwork card (wireless or wired), an infra-red communication device,etc.); and working memory 240, which may include RAM and ROM devices.Optionally, the computing device 200 may include a processingacceleration unit 235, which can include a DSP, a special-purposeprocessor and/or the like. The computer-readable storage media reader225 can further be connected to a computer-readable storage medium,together (and, optionally, in combination with storage device(s) 220)comprehensively representing remote, local, fixed, and/or removablestorage devices plus storage media for temporarily and/or morepermanently containing computer-readable information. The communicationssystem 230 may permit data to be exchanged with a data network and/orwith another computing device within a network, as further explainedbelow regarding FIG. 16.

The computing device may also comprise software elements, shown aslocated within a working memory 240, including an operating system 245and/or other code 250, such as program code implementing a program orcode for operation of the device. The computing device 200 may alsoemploy a GPS receiver 260 for location based capabilities. The GPSreceiver 260 can be used to further exploit data regarding geographicaland /or weather conditions to improve the operational efficiency ofdevice. For example, the GPS receiver can be used to download dataregarding orientation and duration of sunlight and the direction(s) ofprevailing winds. This data can be used to update or improve thealgorithms to obtain better efficiencies for solar energy extraction andto minimize fan power needs. The computing device 200 may other includea radio transceiver 265 that enables the device to have a wirelesscommunications capability. A particular radio communications protocolmay be employed depending upon geographical limitations where the deviceis installed, enabling the device to maintain wireless communicationswith a wireless communications network.

Alternate components of the computing device might also be used and/orparticular elements might be implemented in hardware, software(including portable software, such as applets), or both. Further,connection to other computing devices such as network input/outputdevices may be employed.

Although the device has been described with the use of a computingdevice 200, it is also contemplated that the device may also becontrolled by one or more microcontrollers. A microcontroller is anintegrated chip including a central processing unit (CPU), a memoryelement (such as RAM or ROM), a group of input/output ports, and timers.Microcontrollers, however, are typically designed to execute only alimited number of tasks because of the limited processor capabilitiesand therefore, are limited in terms of their ability to monitor numerousinputs and to generate numerous command outputs. Nonetheless, because ofthe relatively few inputs and outputs of the device, a microcontrollerin combination with a communications element, such as a transceiver witha wireless capability, remains as a viable solution in terms ofproviding control for the device.

The computing device or microcontroller(s) may also be incorporatedwithin a communications network, as shown in the FIG. 17. The FIG. 17 isintended to illustrate that either a computing device ormicrocontroller(s) be represented by the reference numeral 200. Further,the FIG. 17 is intended to illustrate an example communication system300 that may be used in connection with the device and method disclosedherein. The system 300 may include one or more remote general purposecomputers 305 and 310 that communicate through a communications network310 with one or more of the devices 10, each with their own integralcontroller/microprocessor(s) 200. By way of example, the general purposecomputers may be personal computers and/or laptop computers runningvarious versions of Microsoft Corp.'s Windows™ and/or Apple Corp.'sMacintosh™ operating system(s) and/or workstation computers running anyof a variety of commercially-available UNIX™ or UNIX-like operatingsystems. These remote computers 305 and 310 may also have any of avariety of applications, including for example, database client and/orserver applications, and web browser applications. Alternatively, theuser computers 305 and 310 may be other electronic devices, such as anInternet-enabled mobile telephone, and/or personal digital assistant,capable of communicating via the network 320 and/or displaying andnavigating web pages or other types of electronic documents. Althoughthe exemplary system 300 is shown with two remote computers, any numberof remote computers may be supported.

The network 320 may be any type of network familiar to those skilled inthe art that can support data communications using any of a variety ofcommercially-available protocols, including without limitation TCP/IP,SNA, IPX, AppleTalk, and the like. Merely by way of example, the network320 maybe a local area network (“LAN”), such as an Ethernet network, aToken-Ring network and/or the like; a wide-area network; a virtualnetwork, including without limitation a virtual private network (“VPN”);the Internet; an intranet; an extranet; a public switched telephonenetwork (“PSTN”); an infra-red network; a wireless network (e.g., anetwork operating under any of the IEEE 802.11 suite of protocols, theBluetooth™ protocol known in the art, and/or any other wirelessprotocol); and/or any combination of these and/or other networks.

The system 300 may also include one or more server computers 325. Theserver 325 may be a web server, which may be used to process requestsfor web pages or other electronic documents from user computers 305 and310. The web server can be running an operating system including any ofthose discussed above, as well as any commercially-available serveroperating systems. The web server 325 can also run a variety of serverapplications, including HTTP servers, FTP servers, CGI servers, databaseservers, Java servers, and the like. In some instances, the web server325 may publish operations available as one or more web services.

The system 300 may also include a database 335. The database 335 mayreside in a variety of locations. By way of example, database 335 mayreside on a storage medium local to (and/or resident in) one or more ofthe computers 305, 310, or on a storage medium local to one or more ofthe controllers/microprocessor(s) 200 of the devices 10. Alternatively,the database 335 may be remote from any or all of the computers orcontrollers, and in communication (e.g., via the network 320) with oneor all of the computers and controllers. The database 335 may reside ina storage-area network (“SAN”) familiar to those skilled in the art.Similarly, any necessary files for performing the functions attributedto the computers and/or controllers/microprocessors may be stored remotefrom or locally on the respective computers or controllers. The database335 may be a relational database, such as Oracle 10i™, that is adaptedto store, update, and retrieve data in response to SQL-formattedcommands.

As also shown in the FIG. 17, the controllers/microprocessor(s) 200 eachcommunicate with other components of the system 300 through the network320. Although the controllers/microprocessors 200 may have thecapability to independently operate and control their correspondingdevices 10, additional features of the invention may be available whenthe controllers are incorporated within the communication system 300.For example, if a device is moved from one location to another, thecontroller could receive updated algorithms that provide more closelymatched programming features corresponding to the particular environmentin which the devices may operate. Additionally, software or othercommand updates may be downloaded to the controllers/microprocessorsthereby eliminating the need for manual software updates. Additionally,information may be uploaded from the controllers/microprocessors. Thisinformation may be used as historical operating data to improve softwareprogramming or other aspects of control for the devices. Since thedevices may be operating in remote or austere conditions, the capabilityfor the controllers to communicate through a communications network canprovide other benefits. For example, if a controller experiences amalfunction or suffers from a reduced functional capacity, it would bepossible to bypass control of the device as normally provided by thecontroller/microcontroller by commands sent through one or more of theremote computers. In the event there are a multitude of devicesfunctioning simultaneously within one or more locations, the computingcapability of the server 325 may be advantageous in providing additionalor supplemental control to the devices. Additionally, the database 335can be useful in compiling operational data for the devices in order toimprove the sets of algorithms and software commands that may beassociated with operation of the devices. Those skilled in the art canappreciate other advantages of incorporating a device 10 within acommunication system 300.

In accordance with methods of the present invention, a device removeswater vapor from an incoming, ambient airstream. The exhaust airstreamleaving the device is therefore a dried or water lean airstream.Operation of the device can conceptually be divided into two maincycles, namely, a charge cycle and an extraction cycle. In the chargecycle, the ambient airstream is passed through a chamber, across adesiccant stack, and back to the environment. The desiccant absorbswater vapor in the air stream. The desiccant is preferably employed in aliquid solution with water. The desiccant solution is distributed in thechamber by a desiccant media, including a plurality of media sheets,preferably in folded media sheets configured within media cartridgesdisposed in each tray of the desiccant stack.

In accordance with the methods, a charge cycle includes absorption ofwater vapor, and controlling the amount of water vapor removed from theairstream such that the desiccant solution does not become oversaturated with water. In arid climates, it may be advantageous to runthe charge cycle during nighttime hours when the relative humidity risesdue to a corresponding drop in ambient air temperature. A controlledflow of air is passed through the chamber of the device by one or morefans. As set forth above in the illustrated preferred embodiment, one ormore fans may be located at the entrance to the chamber, coupled withone or more fans located at the exit of the chamber. Airflow sensorsalong with temperature and humidity sensors monitor the state of thechamber. An optimum airflow through the chamber is achieved to match thedesired quantity of water to be recovered. If a relatively small amountof water is the recovery requirement, then a smaller volume of air ispassed through the chamber as compared to a larger water recoveryrequirement that must be attained in the same amount of operation time.Once the desiccant media has absorbed the requisite amount of water forthe charge cycle, an extraction cycle is commenced. First, the chamberis isolated from the ambient airstream by closing all valves or dampersthat communicate with the surrounding environment. Heat energy is addedto the chamber. This may be achieved by use of a heat exchanger that hasmany possible sources of power. Heat energy is added to a predeterminedpoint in which vaporization occurs for the water within the chamber. Atthis point, the moist air within the chamber can be circulated through acondenser. Preferably, the condenser does not require a separate sourceof power for cooling. Rather, it is preferred to initiate condensingwhen the internal temperature within the chamber exceeds a dew pointtemperature relative to the external ambient temperature. Accordingly,the cooling “source” for the condenser is simply the ambient air, and aflow of ambient air is passed through the condenser to achievecondensing of the moist chamber air. The condenser has a passageway,typically defined by a cooling coil, in which the cooler temperature ofthe coil causes the water vapor to condense. Water droplets condensed onthe surfaces of the condensing coil are collected in a container thatcommunicates with the condensing coil. During this condensing phase ofthe extraction cycle, heat continues to be added to the chamber for aperiod of time to evaporate a desired amount of water trapped within thechamber. Accordingly, recirculation of the air within the chamber occursin which a return line is provided from the condenser back to thechamber. In addition to adding heat to the chamber, the vaporizationtemperature of the water can be more easily achieved by reducing thepressure within the chamber. For example, a partial vacuum can be drawnfor the air within the chamber, and the remaining amount of air withinthe chamber can be heated and re-circulated during the condensing phase.

Further in accordance with methods of the invention, it is contemplatedthat optimal desiccant solution ratios are maintained for each reservoirof solution within each tray. Liquid level sensors along with chemicalconcentration sensors may be employed in each tray to monitor liquidlevels and desiccant concentrations. As needed, desiccant solution canbe replaced and/or water may be automatically added to each tray assupplied from supply reservoirs that communicate with each of the trays.

Further in accordance with methods of the invention, the dried airstreamthat is produced during a charge cycle can be used to condition theinterior airspace of a man-made structure. Accordingly, duct work may beconnected to the exhaust airstream interconnecting the exhaust airstreamwith the interior airspace.

Also in accordance with methods of the invention, the modularconstruction of the device allows for easily changing the water recoverycapacity of the device. Therefore, it is contemplated that waterrecovery capability can be optimized by changing the number of traysused by changing the exposed surface area of the media cartridges,and/or changing the flow path of air through the chamber. As discussed,a serial flow path through the chamber or a parallel flow path throughthe chamber changes the dwell time of the airstream within the chamber.These different flow paths also result in greater or lesser contact ofthe desiccant media with the airstream which, in turn, alters the rateat which water is absorbed by the desiccant. Additionally, the flow rateof air through the chamber of the device can also be adjusted to meetthe desired water recovery requirement. In general, a greater flow rateof air through the chamber should result in a greater amount of waterrecovered as compared to a lesser flow rate.

Also in accordance with methods of the invention, it is contemplatedthat dynamic programming is used with a controller/microprocessor tooptimize device operation. Within the controller/microprocessorprogramming, algorithms can be used that establish base line or initialoperation parameters based upon known environmental factors. Theseenvironmental factors include daily temperature data, daylight data,humidity data, wind data, and potential damage scenario data. Each ofthese factors may ultimately affect the operation of the device. Withrespect to temperature and humidity data, this data will partiallydetermine optimum times for operating the cycles of the device. Thedaylight data also helps to define when temperature and humidity changeswill most rapidly occur during average temperature conditions. Wind datacan be used to ensure the device is oriented in the proper directionsuch that a constant flow of air can be provided through the devicewithout undue affects of adverse wind conditions. Potential damagescenarios relate to the specific location where the device is placed,and the chances that a human or environmental event will damage ordestroy the device. By evaluating each of these factors as compared todifferent geographical locations, initial setup and operation of adevice is simplified and initially optimized. As a particular device isplaced into operation, continued monitoring of environmental conditionsalong with the operational capability of the device can be used to alterthe initial operational algorithms to then establish optimal operationalparameters. Because multiple devices may be employed in austere ordifficult to travel locations, it is also advantageous to incorporatethe devices within a communications network in which operation of thedevices may also be controlled remotely. For example, consider a devicethat has been damaged, or has one or more components that are notfunctioning to capacity. In this scenario, commands may be issued from aremote computing device to change the current operational algorithms tocompensate for the damage to components. One specific example couldrelate to a component such as a fan or valve that has limitedfunctioning, and therefore, the operational algorithm could be modifiedto change the operation of these elements in order to meet the desiredwater recovery goal.

Also in accordance with methods of the present invention, it may bepossible to determine the optimum times for running a charge cyclesimply by evaluating nighttime hours. For example, light sensors and atime of day clock may be used by the controller to initiate andterminate a charge cycle, the conclusion in this method of control beingthat nighttime hours are the best for running the charge cycle.

Further in accordance with methods of the invention, it is contemplatedthat the recovered water may be further treated to ensure it is potable.For example, a number of additional water treatment measures may betaken to make the water potable. Such measures may include filtration,exposure to ultraviolet light, mineralization, chlorination, and/orfurther chemical treatment.

Further in accordance with methods of the invention, it is contemplatedthat in lieu of a single heat exchanger, a desiccant stack may takeadvantage of multiple heat exchanging assemblies powered by a singlesource of power. Accordingly, selected trays within a desiccant stackmay be disposed between one or more heat exchanging assemblies in whicheach assembly has a heating line, a heat distribution element, andsensors. These assemblies may each have their own housing, or the traysmay be modified to incorporate the heat exchanging assemblies in which asingle housing can be used for both a desiccant tray and heat exchangingassembly combination.

While illustrative embodiments have been described in detail herein, itis to be understood that the concepts may be otherwise variouslyembodied and employed, and that the appended claims are intended to beconstrued to include such variations, except as limited by the priorart.

What is claimed is:
 1. A water recovery device comprising: a desiccantstack including a chamber defining an airflow path therein, thedesiccant stack including a plurality of desiccant trays, each desiccanttray including a desiccant media cartridge and an amount of liquiddesiccant placed within the desiccant tray and being absorbed by a mediamaterial of the media cartridge; a condenser communicating with thedesiccant stack; a heat source operative to add heat energy to thechamber; and wherein an airstream within the water recovery device iswarmed prior to or during an extraction cycle, the extraction cycleoperative to remove a retained water vapor from within the chamber, thecondenser providing a cooling source to condense the water vapor andthereby producing an amount of water condensate.
 2. A water recoverydevice, as claimed in claim 1, wherein the heat energy is added to thechamber using a water or glycol-based heat exchanger.
 3. A waterrecovery device, as claimed in claim 2, wherein the heat exchangerfurther includes a heating element disposed below a heating line, theheating line transferring heat to the heating element, and wherein theheating element is disposed within an airflow path.
 4. A water recoverydevice, as claimed in claim 3, wherein the heating line communicateswith a heat source, the heat source configured to regulate a temperatureof the heating line such that the temperature of the heating line isincreased when the temperature of the heating line falls below atemperature threshold.
 5. The water recovery device, as claimed in claim3, further including an electrical heating element, the electricalheating element adding heat energy to the chamber and being disposedwithin the defined airflow path of the chamber.
 6. The water recoverydevice, as claimed in claim 5, wherein the electrical heating elementand the heat exchanger simultaneously add heat energy to the chamber. 7.A water recovery device recovery device, as claimed in claim 1, whereinthe heat source is configured to regulate a temperature of a heatingline such that the temperature of the heating line is increased when thetemperature of the airstream falls below a temperature threshold.
 8. Awater recovery device, as claimed in claim 1, wherein an electricalheating element adds heat energy to the chamber, and wherein theelectrical heating element is disposed within the defined airflow pathof the chamber.
 9. A water recovery device, as claimed in claim 8,wherein the electrical heating element is disposed in at least onedesiccant tray such that an airflow is warmed prior to flowing past adesiccant media located in the desiccant tray.
 10. The water recoverydevice, as claimed in claim 1, further including an electrical heatingelement, wherein at least one desiccant tray includes a desiccant mediacartridge, the electrical heating element disposed within an airflowpath such that an airflow is warmed before passing the desiccant mediacartridge.
 11. A water recovery system comprising: (a) a water recoverydevice including: (1) a desiccant stack including a chamber defining anairflow path therein, the desiccant stack including a plurality ofdesiccant trays, each desiccant tray including a desiccant mediacartridge and an amount of liquid desiccant placed within the desiccanttray and being absorbed by a media material of the media cartridge; (2)a condenser communicating with the desiccant stack; (3) a heat sourceoperative to add heat energy to the desiccant stack; wherein anairstream within the water recovery device is warmed prior to or duringan extraction cycle, the extraction cycle operative to remove a retainedwater vapor from within the chamber, the condenser providing a coolingsource to condense the water vapor and thereby producing an amount ofwater condensate; (b) a controller incorporated in the device forcontrolling functioning of the water recovery device to include anextraction cycle, the water recovery device further including aplurality of sensors as inputs to the controller, and a plurality ofvalves as outputs of the controller, the valves being located within aheat transport line of the water recovery device; and (c) acommunications node incorporated within a communications system enablingthe water recovery device to communicate within the communicationssystem.
 12. A water recovery system, as claimed in claim 11, wherein theheat energy is added to the desiccant stack using a water orglycol-based heat exchanger.
 13. A water recovery device, as claimed inclaim 12, wherein the heat exchanger further includes a heating elementdisposed below a heating line, the heating line transferring heat to theheating element, and wherein the heating element is disposed within anairflow path.
 14. A water recovery device, as claimed in claim 12,wherein an electrical heating element adds heat energy to the desiccantstack, and wherein the electrical heating element is disposed within thedefined airflow path of the desiccant stack.
 15. The water recoverydevice, as claimed in claim 14, wherein the electrical heating elementand the heat exchanger add heat energy to the desiccant stacksimultaneously.
 16. A water recovery device, as claimed in claim 11,wherein the heating line communicates with a heat source, the heatsource configured to regulate a temperature of the heating line suchthat the temperature of the heating line is increased when thetemperature of the heating line falls below a temperature threshold. 17.The water recovery device, as claimed in claim 11, further including anelectrical heating element, the electrical heating element disposedwithin an airflow path such that an airstream is warmed before passingthe desiccant media cartridge.
 18. The water recovery device, as claimedin claim 11, further including an electrical heating element, theelectrical heating element adding heat energy to the desiccant stack andbeing disposed within the defined airflow path of the desiccant stack.